Method of and machine for producing gears



Jan. 4, 1938.

A. H. CANDEE METHOD OF AND MACHINE FOR PRODUCING GEARS Filed NOV. 16. 1935 5 Shee ts-Sheet 1 3nventor Gttorneg Jan. 4, 1938. A. H. CANDEE 2,104,184

METHOD OF AND MACHINE f'OR PRODUCING GEARS Filed Nov. 16. 1935 5 Sheets-Sheet 2 Snventor (Ittorneg HNU I'LHNINU,

Jan 4, 1938. CANDEE 2,104,184

METHOD OF AND MACHINE FOR PRODUCING GEARS v Filed Nov. 16, 1935 I 5 Sheets-Sheet a iu f w w (all Gttorngg Zhwcntor Jan. 4, 1938. A. H. CANDEE METHOD OF AND MACHINE FOR PRODUCING GEARS Filed Nov. 16. 1935 5 Sheets-Sheet 4 3rwcntor Gttorneg Jan. 4, 1938. v A. H. CANDEE 2,104,134

METHOD OF AND MACHINE PRODUCING GEARS Filed Nov. 16, 1935 5 Shats-Sheet 5 3nventor attorney tutu rumnw,

rarentea Jan. 4, won

UNITED STATES PATENT OFFICE METHOD OF AND MACHINE FOR PRODUC- ING GEARS tion of New York Application November 16, 1935, Serial No. 50,225

27 Claims.

The present invention relates to methods and machines for producing irregular gears and particularly to methods and machines for producing irregular bevel gears. By the term irregular gear", I mean a gear whose teeth are arranged at varying distances from the axis about which the gear rotates.

The primary purposes of this invention are to provide a theoretically correct method for producing irregular bevel gears and a machine designed to operate automatically according to the method which will at the same time be relatively simple and inexpensive.

Another object of the invention is to provide a generating process for producing irregular bevel gears which may be carried out upon existing machinery for generating regular bevel gears with but slight modification of such machinery.

A further object of the invention is to provide a method for generating irregular gears, either tapered or cylindrical which does not require special cutting tools or any special mounting of such tools but which may be performed with standard tools mounted in standard fashion.

Still another object of the invention is to provide a method of generating irregular gears, either tapered or cylindrical, which permits the use of straight-profiled cutting tools.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

Heretofore, the production of irregular bevel gears has been attempted only rarely and has been a tool-maker's task, tedious and slow and at best'only approximate. After laying out the gears and calculating as well as possible the loca tion of the different teeth, the gears have been made by cutting each tooth individually and usually in a forming or milling operation. No machine has heretofore been available for the automatic generation of the tooth profiles of such gears and no machine has ever been available heretofore for the automatic production of such gears. The accuracy of the gears produced has depended wholly upon the skill of the mechanic and the exactness with which the machines and tools available could approximate the calculated tooth shapes and tooth spacing.

The present invention provides a theoretically accurate method of generating irregular bevel gears and of all irregular gears. It is based upon the theory of gear generation that has so long been successfully applied to the generation of regular gears both bevel and spur, viz.. that a pair of gears generated conjugate to conjugate basic gears will be conjugate to one another. The basic gear to which the irregular gear is generated conjugate may be the same as the basic gear used in generating regular-gears. It may be a rack or a crown gear' and it will have identical teeth, uniformly spaced.

The generating operation is efiected by rolling the blank and tool relative to one another as though the irregular gear being out were rolling with a basic gear represented by the tool. In this generating operation, there are two fundamental differences from the method of generating usual gears. First, the distance between the plane of the tool and the axis of the blank instead of remaining constant must be varied to correspond to the shape of the irregular gear; and second the ratio of relative motions between the tool and blank, instead of remaining constant, must also be varied. In generating an irregular bevel gear, the variation in distance between the axis of the blank and the plane of cut is obtained by varying the angle between the blank axis and the plane of cut during the generation of the different teeth around the blank.

The method of the present invention may be used in generating one or both members of a pair of gears. Thus an irregular gear may be produced which may mesh either with a gear generated as a regular gear or with a gear generated as an irregular gear by the method of this invention. In both cases, the two gears of the pair are generated conjugate to the same basic gear or to conjugate basic gears and hence will mesh correctly with one another.

In the method of the present invention, teeth are generated on an irregular gear which are of correct depth and correctly arranged on the irregular pitch surface of the gear. Moreover, the profile curvatures of different teeth of the gear will vary in accordance with the different radial distances at which the difierent teeth extend from the axis of the gear. This variation in profile shape is essential if the gears out are to roll correctly with their mates, but is a feature which has been more or less neglected heretofore in the production of irregular gears, and has not been attainable in any previously existing methods or machines for production of irregular bevel gears.

The correct spacing of the teeth on the irregular pitch surface of the gear during generation may be achieved in various ways. If a notchedplate type of index mechanism is employed, the spacing of the notches of the index plate may be non-uniform angularly so that the work spindle may be rotated different distances about its axis in successive indexing operations in correspondence to the spacing of the teeth of the gear angularly about its axis. If a worm and wormwheel type of index mechanism is employed and the index worm is driven in time with the cradle movement for generation of the tooth profiles, the rotating index worm may be moved axially at a variable velocity to effect both the variation in roll of tool and blank and also to produce the correct irregular tooth spacing. This latter type of index mechanism is employed on the machine illustrated in the accompanying drawings.

In the drawings I have disclosed particularly how the invention may be applied to the production of straight tooth bevel gears and to this end, I have illustrated specifically how a Gleason twotool straight tooth bevel gear generator such as disclosed in U. S. Patent No. 1,656,633 of January 17th, 1928 may be modified so that it can be employed to generate such irregular bevel gears according to the present invention.

In the drawings:

Fig. 1 is a view, partly in plan and partly in section showing a standard straight tooth bevel gear generator built according to Patent No.

1,656,633 modified so as to cut irregular beveled gears according to the present invention.

Fig. 2 is a fragmentary view looking at the rear of this modified machine, parts being broken away for the purpose of clearness in illustration;

Fig. 3 is a section on the line 3-3 of Fig. 2, looking in the direction of the arrows;

Figs. 4, 5, and 6 are diagrammatic views illustrating different steps in the generation of an irregular bevel gear of approximately elliptical shape according to the process of the present invention;

Figs. 7, 8, and 9 are, respectively, a plan view and two side elevations taken at right angles to one another, respectively, and showing a pair of irregular bevel gears, the larger member of which may be generated according to the method of the present invention; and

Figs. 10, 11, and 12 are similar views showing a pair of elliptical bevel gears. In. this latter case, both members of the pair may be generated by the method of the present invention.

Reference willbe had first to Figs. 4 to 6 inclusive which illustrate the underlying principle of producing gears according to the present invention. In these figures, l0 designates the pitch surface of an elliptical or other irregular gear whose axis is denoted at H. I2 is the pitch plane of a rack or crown gear to which this irregular gear is to be generated conjugate. A3 and I 4 denote a pair of reciprocating planing p mpmitioifidafidloperated relative to thebia'nk as to "represent" oppositsid toom surfaces-+Hnd-46,..respfii tiyellmLthe gggly An irregular gear whose pitch surface i0 is to roll without slipping on the pitch plane 12 of a rack or crown gear must have teeth which are uniformly spaced around its surface I 0 and which are of varying profile shape corresponding to their different distances from the axis ll of the gear. If the teeth of the rack or of the crown gear are of straight profile. as shown, the teeth of the gear will be of involute profile: in this case not involutes of a circle but involutes of a base curve of a shape dependent upon the shape of the pitch surface of the gear. As the irregular gear rolls with the rack or crown gear. the distance between its axis II and the pitch plane [2 of the and it is so illustrated in the drawings.

rack or crown gear changes as is clearly shown in Figs. 4 to 6 inclusive. Fig. 4 indicates a position of generation at the end of the major axis of the ellipse i0. Fig. 6 indicates a position of generation at the end of the minor axis of the ellipse, and Fig. indicates a. position of generation intermediate the positions of Figs. 4 and 6.

In the generation of an irregular gear according to the present invention, the blank is rolled relative to the cutting tools as though the irregular pitch surface Hl of the gear were rolling without slipping on the pitch surface l2 of the basic generating gear or rack. Thus, teeth will be generated on the work which will be truly conjugate to the basic rack or crown gear. When the other member' of the pair, whether it be a regular gear or an irregular gear, is generated conjugate to the same rack or crown "gear or conjugate to a rack or crown gear which is conjugate to the first rack or crown gear, the two members of the pair will be conjugate to one another. In the generation of an irregular gear according to the present invention, then, the distance between the axis of the blank and the plane of the rack or crown gear or the plane of cut is changed for generation of different teeth of the blank and the blank is rolled at a varying velocity relative to the cutting tools for and during the generation of different teeth so as to produce the required variance in tooth profile. The required uniformity of spacing of the teeth'on the irregular pitch surface of the gear may be obtained either directly by predetermined non-uniform indexing movements of the blank on its axis or equivalently by a motion of the machine in which the tools are indexed relative to the blank in accordance with the equal spacing of the teeth of the basic gear or rack to which the gear being cut is generated conjugate. .4 The motions required to generate irregular 4U gears correctly are provided in the modified straight tooth bevel gear generator shown in the accompanying drawings.

designates the frame of the machine. Upon this frame at one end thereof is mounted the upright or cradle housing 2|. Upon the other end of the frame is mounted the sliding base 22 (Fig. 2).

The tool end of the machine may be identical in construction with the tool end of the machine shown in the Head et al. patent above mentioned The cutting tools, of which only one, T, is shown in the drawings are mounted in clapper-blocks 24, of which only one is showr an e c apperoc s We mounted upon slides 25, of which only o nejsshown. The slides 25 51 lama tool arms 26, of which only one is shown, which are angularly adjustable upon the face 28 of the cradle 30. The cradle is journaled in the housing 2| in suitable bearings, of which one is indicated at 3|, and is guided in its oscillatory movement by the circular V-shaped way 32 which is formed upon the cradle housing.

The cutting tools are reciprocated to efi'ect alternate cutting and return strokes, the tools being withdrawn from cutting position on their return strokes by the clapping mechanism. The cradle rolls in one direction during generation of a tooth of the gear blank and when the blank is withdrawn for indexing, the cradle is-rolled back in the opposite direction to return it to its original position. All this is an old and known method of construction and operation and is fully disclosed 75 in the Head et al. patent and need not further be described here.

The work end of the machine is, however, substantially modified from the construction shown in the Head et al. patent. Mounted upon the sliding base 22 is a swinging base 35. This base 35 is mounted to swing about the axis at (Fig. 1) which, for a bevel gear, is perpendicular to the axis of the blank and intersects the blank axis in the blank apex. The swinging base 35 is retained on the sliding base 22 and is guided in its swinging movement thereon by the arcuate gib 35 which is secured to the swinging base and engages the arcuate guide-flange 31 formed on the swinging base 22 concentric with the axis a.

Mounted upon the swinging base 35 is the work head 48 which, as is usual, is adjustable on the swinging base in the direction of the axis of the work spindle. The work spindle 4| is journaled in suitable bearings 42 and 43 in the work head and to the rear end of the work spindle is keyed the index worm wheel 45. The gear blank G to be cut is secured to the front end of the work spindle by any suitable means.

The index worm wheel 45 is driven from the change gears 45, 41, 48, and 48 through the shaft 55, the bevel mitre gearing 5| and 52, the shaft 53 and the index worm 54. The change gears may be driven through gearing similar to that disclosed in the Head et al. patent so that during cutting, the rotation of the work spindle will be timed to the rotation of the cradle and so that periodically the work spindle may be indexed.

5U designates a yoke member which is fixedly connected to the worm shaft 53 through the thrust bearings iii. The outer races of these bearings are secured against a shoulder formed internally in the yoke member by the cap member 52, which may be secured to the yoke member by screws or the like. The inner races of these bearings are secured against a shoulder formed on the shaft 53 by the spur pinion 54, which is keyed to the worm shaft 53 and which is held against longitudinal movement on said shaft by the nut 55.

Journaled in the yoke member 50 is a stubshaft 66 upon which is rotatably mounted a roller 61, the mounting comprising a pair of anti-friction bearings 88. The roller 51 is adapted to engage with the periphery of a cam 10 that is keyed to a shaft 'II which is journaled on anti-friction bearings 12 and 13 in the work head.

The yoke member 50 is formed with an elongated opening so that it may straddle the shaft H and be free to move at right angles thereto.

The yoke member is mounted to slide in the bearings l5 and 15 formed in the work head, the hearing 15 receiving the guide stud 11 which projects from; one end of the yoke member.

The cam 78 is driven from the worm shaft 53 through the spur pinion 54, the spur gear 88 (Fig. 3), which meshes with this spur pinion, the worm 8|, which is keyed to the shaft 82 to which the spur gear 85 is fastened, and the worm wheel 84 which meshes with the worm 8i and is keyed to the shaft II.

There is a second cam 85 keyed to the shaft II. This cam engages a roller 85 which is mounted upon stub-shaft 81 that is journaled in a bracket 88. The bracket 88 is mounted upon the sliding base 22 and is angularly adjustable thereon about the axis 1:. It is secured at any adjusted position by the bolts 98 (Fig. 1) which engage in the arcuate slot 9! that is formed in the sliding base 22 concentric of the axis 1'.

The cam 85 is held against the roller 85 by a spring-pressed plunger 82, which is housed in a. bracket 93' and is urged against one side of the swinging base 35 by the coil spring 85. The bracket 83 (Fig. 1) is mounted upon the sliding base 22 and is angularly adjustable thereon about the axis a: and is secured in any position of its angular adjustment by a bolt 85 which engages in the arcuate slot 8|.

The roller 51 is held in engagement with the cam 18 by operation of the coil spring 81. This coil spring is mounted in the housing 98 and surrounds the stud 99 which is secured in the projection H of the yoke member 50. The coil spring is interposed between the inside end wall of the housing 88 and the washer Hill which seats against the outer end face of the projection 11 of the yoke member. The housing 98 is secured to the work head by screws (not shown) or in any other suitable manner.

The gear is a change gear and the gearing 54-85 is selected in accordance with the number of lobes in the irregular gear which is to be generated. For a single-lobe or elliptical gear rotating about a focus the ratio of the gearing 54-88 will be such that the cam shaft H makes one revolution while the index worm wheel 45 is making one revolution, that is, the cam shaft H will make one revolution during the cutting of the gear. For a two-lobed irregular gear, the cam shaft II will be geared to make two complete revolutions while the index worm wheel is making one revolution, etc.

From the preceding description, it will be apparent that as the cam shaft H rotates on its axis, a swinging movement will be imparted to the swinging base 35 through operation of the cam and that simultaneously an axial motion will be imparted to the index worm shaft 53 through operation of the cam 18. The cams i8 and 85 are designed in accordance with the gear to be cut to impart nonuniform motions to the worm shaft 53 and swinging base 35. respectively, in accordance with the shape of the pitch surface of the gear to be generated, The swinging motion of the base 35 changes the distance between the axis of the work and the plane of cut as different teeth of the gear are cut, in accordance with the positions of these teeth on the irregular pitch surface of the gear being generated. The axial motion of the worm shaft 53 combines with the rotation of this shaft to produce the variation in tooth profile of different teeth in the gear during cutting of those teeth and it operates, dur ing indexing, to effect the variation in spacing of the teeth of the blank on a surface concentric of the blank which is required to produce the uniform spacing of these teeth on the irregular pitch surface of the blank. The indexing operation can be considered in another aspect, however, as an indexing of the tools on the equally spaced teeth of the basic crown gear.

In setting up the machine for operation, the swinging base 35 is adjusted angularly on the sliding base 22 to adjust the blank to its pitch cone angle. The bracket 85 and bracket 83 are adjusted on the sliding base 22 in accordance with this angular adjustment of the work so that the roller 85 may engage the cam 85 and the plunger 82 may engage the swinging base 35, respectively.

. In operation of the machine, the work is fed into the reciprocating tools by movement of the sliding base 22 and then the reciprocating tools are rolled with the blank to generate one of 7 the teeth of the blank by rotation of the cradle and rotation of the work spindle. The work spindle is rotated by operation of the worm 54 which is driven at a uniform velocity in time with the cradle movement through the mitre gears 5| and 52 and is simultaneously moved axially at a variable velocity by operation of the cam 10. During generation of the tooth, also, a very slight angular displacement of the axis of the work about the center a may take place under actuation of the cam 85.

After one tooth of the blank has been generated, the work is withdrawn from engagement with the tools by withdrawal of the sliding base 22. Then the work is indexed through operation of the indexing mechanism of the machine, which may be the same as in the Head et a1. patent. This indexing motion is superimposed upon the axial movement of the index worm shaft under actuation of the cam 10. After the work has been indexed, it is again returned into engagement with the tools and another tooth is generated in the manner described. Due to the continuous rotation of the cam 85 the angle between the work spindle and the tools is constantly changed so that successive teeth of the gear are generated'with the axis of the work spindle extending at difierent angles to the plane of cut of the tools. Due to the continuous rotation of the cam 10, successive teeth of the blank are generated with difierent tooth profile curvatures and also due to the operation of the cam 10, in successive indexing operations, the blank is turned different amounts about its axis so that the teeth will be properly spaced on its irregular pitch surface.

Figs. 7 to 9 inclusive illustrate one possible application of the present invention. Here a pair of bevel gears are shown comprising a gear H and a pinion III. e gear H0 is a two-lobed irregular gear and may be generated according to the process of the present invention and upon the machine described. The pinion III is a singlelobed pinion which may be generated by the method of the present invention but preferably is generated as a regular bevel pinion upon a standard machine, for instance, upon the machine of the Head et a1. patent. It is bored eccentrically, as indicated at H so that it may be meshed correctly with the irregular gear H 0. It is to be noted that the bore H5 in the pinion is so located that the axis H3 about which the pinion rotates will intersect the axis H2 of the gear in the common cone apex H4 of pinion and gear. Since the irregular gear H0 is generated according to the method of this invention to be conjugate to a regular crown gear, it will mesh correctly with the regular pinion III which is also generated to be conjugate to a regular crown gear. To assure that the irregular gear H0 will have teeth suitable to mesh correctly with the teeth of the pinion Ill, it is only necessary to design the cams I0 and 85 so that gear H0 will be generated conjugate to the same basic crown gear to which the pinion III was generated conjugate.

A further application of the present invention is shown in Figures 10 to 12 inclusive. I and l2l designate a pair of single-lobed irregular or elliptical mitre gears. These gears are identical with one another and both may be generated according to the process of the present invention. They are so bored and mounted that their axes of rotation I22 and I23, respectively, intersect in a common apex or center I24.

While the invention has been described in connection with production of gear pairs in which the tooth profiles of both members are generated, it will be understood that it is equally applicable to production of the generated member of a pair of which one member is a non-generated gear. In this latter case, the non-generated member of the pair becomes the basic gear to which the generated member is generated conjugate according to the principles of this invention. Further, while the invention has been described in connection with the generation of straight-toothed irregular gears, it will be understood that it is equally applicable to the production of curved tooth irregular gears.

Various other possible applications of this invention will be apparent to those skilled in the art. This application is intended to cover any adaptations, uses, or embodiments of the present invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the gear art and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. The method of generating irregular gears which comprises imparting a cutting motion to the tool while producing a relative rolling motion between the tool and blank as though the gear being cut were rolling without slipping with a basic gear, other than its mate, represented by the tool and having identical teeth, uniformly spaced.

2. The method of generating an irregular gear which comprises employing a cutting tool having a straight cutting edge, and imparting a cutting; motion to the tool while producing a relative r011 ing movement between the tool and the blank as though the gear being out were rolling without slipping upon a basic gear represented by the tool and having straight-profiled, identical teeth, uniformly spaced.

3. The method of generating an irregular gear which comprises generating each tooth of the gear by imparting a cutting motion to a tool while producing a relative rotary movement between the tool and the gear blank about the axis of the blank and simultaneously effecting a relative movement of translation between the tool and blank, and varying the distance between the axis of the blank and the plane of cut of the tool and also the ratio of such relative rotary and translatory movements during generation of different teeth of the blank in accordance with the irregularity of the pitch surface of the gear and indexing the blank different distances for successive teeth of the blank.

4. The method of generating an irregular tapered gear which comprises generating each tooth of the gear by imparting a cutting motion to the tool while producing a relative rolling motion between the tool and the gear blank to generate the tooth profiles of the blank, and varying the velocity of said relative rolling movement and the angle between the axis of the blank and the cutting plane of the tool for generation of different teeth of the blank.

5. The method of generating an irregular gear which comprises moving the tool and blank alternately into and out of cutting engagement, and, while the tool and blank are in cutting engagement, effecting a relative rolling movement between the tool and blank to generate the tooth profiles and indexing the blank diiierent distances for successive teeth oi the blank during the periods oi disengagement oi the tool irom the blank, the velocity of said relative rolling movement being varied for generation oi difierent teeth around the blank and the distance between the axis of the blank and the plane of out also being varied during generation of different teeth of the blank.

6. The method oi generating an irregular gear which comprises moving the tool and blank alternately into and out of cutting engagement, producing a relative rolling movement between the tool and blank to generate the tooth profiles, and varying the distance between the axis of the blank and the plane of cut of the tool and also the ratio oi said rolling movement for generation oi different teeth of the blank and rotating the blank through different angular distances during the periods of withdrawal to index the blank.

7. The method of generating an irregular gear which comprises moving the tool and blank alternately into and out of cutting engagement and, while the tool and blank are in engagement, imparting a cutting movement to the tool and producing a relative rolling movement between the tool and blank to generate the tooth profiles, and varying the distance between the axis oi the blank and the plane oi cut of the tool continuously and also the ratio of said relative rolling movement during cutting of the difierent teeth of the gear, and indexing the blank during the periods of disengagement of the tool from the blank.

8. The method oi generating an irregular tapered gear which comprises generating each tooth of the gear by imparting a cutting motion to the tool while rotating the blank on its axis and simultaneously producing an additional relative movement oi translation between the tool and blank and varying both the angle between the axis of the blank and the plane of cut of the tool and the ratio oi the relative rotational translatory movements for generation of different teeth oi the blank.

9. The method of generating an irregular tapered gear which comprises generating each tooth of the gear by imparting a cutting motion to' a tool while rotating the gear blank on its axis and simultaneously producing an additional relative movement of translation between the tool and blank, and varying continuously the angle between the axis of the blank and the plane of cut of the tool during generation of different teeth of the blank and also varying the ratio oi the relative rotational and translatory movements during generation of diiierent teeth of the blank.

10. The method oi generating an irregular tapered gear which comprises generating each tooth of the gear by imparting a cutting motion to the tool while rotating the gear blank on its axis and simultaneously producing an additional relative movement between the tool and blank about another axis angularly disposed to the blank axis, and varying the angle between the blank axis and the last named axis for generation of different teeth oi the blank and during generation of each tooth, and also varying the ratio of movements 01 the tool and blank for generation of diflerent teeth oi the blank and during generation oi each tooth.

11. The method of generating an irregular gear which comprises generating each tooth of the gear by imparting a cutting motion to a tool while rotating the gear blank on its axis and simultaneously producing an additional relative movement of translation between the tool and blank, and varying the angle between the blank axis and the plane oi cut oi the tool for generation of difierent teeth of the blank and during generation of the different teeth, and also varying the ratio of relative rotation of the tool" and blank for generation oi different teeth of the blank and during generation of each tooth.

12. In a machine for generating irregular gears, tool mechanism, means for actuating the tool mechanism, means for rotating the blank on its axis and simultaneously effecting a relative movement of translation between the tool mechanism and the blank to generate the tooth profiles, and means for varying the ratio of said rotary and translatory movements for generation of diflerent teeth of the blank and during generation of each tooth and means for indexing the blank periodically but through different distances for successive teeth oi the blank.

13. In a machine for generating irregular gears, tool mechanism, means for actuating the tool mechanism, means for rotating the gear blank on its axis and for simultaneously efiecting a relative movement of translation between the tool mechanism and the blank, and means for varying the distance between the axis of the blank and the plane of cut of the tool for cutting different teeth of the blank and during the cutting of each tooth and means for indexing the blank periodically but through different distances for successive teeth of the blank.

14. In a machine for generating irregular tapered gears, a work spindle, tool mechanism, means for actuating the tool mechanism, means for rotating the gear blank on its axis and for simultaneously effecting a relative movement of translation between the tool mechanism and the blank about an axis inclined to. the blank axis, and means for varying the angle between the described axis and the axis of the blank for cutting different teeth of the blank, and means for varying the ratio of said relative rotary and translatory movements for cutting different teeth of the blank.

15. In a machine for generating irregular gears, a work spindle, a cutting tool having a straight cutting edge, means for actuating the tool, means for rotating the work on its axis and for simultaneously producing a relative movement of translation between the work and the tool mechanism to generate the tooth profiles, means for varying the ratio of said rotational and translatory movements for diflerent teeth of the gear and during generation of each tooth, and means for varying the distance between the axis of the work and the plane of cut of the tool for generation oi different teeth of the gear and during generation of each toothand means for indexing the work periodically but through difierent distances for successive teeth.

16. In a machine for generating irregular gears, a work spindle, tool mechanism, a carrier upon which one of said parts is mounted, means for moving the tool mechanism and the work alternately into and out of cutting engagement, means for rotating the work spindle and carrier at uniform velocities in timed relation during cutting, means for superimposing upon the motions oi the work spindle or carrier an additional motion which is at a varying velocity during generation of diiierent teeth of the blank, means for varying the distance between the axis of the blank and the plane of cut oi the tool mechanism during cutting of different teeth of the blank and means for indexing the blank during the periods of withdrawal.

17. In a machine for generating irregular gears, a rotatable work spindle, tool mechanism, a cradle upon which one of said parts is mounted and which is oscillatable about an axis inclined to the axis of the work spindle, means for rotating the work spindle continuously at a varying velocity, means for moving the work spindle and the tool mechanism alternately into and out of cutting engagement means for actuating the tool mechanism, means for rotating the cradle at a uniform velocity during cutting, means for imparting to the work spindle, during cutting, a uniform motion in addition to its non-uniform motion and timed to the uniform motion of the cradle and to said non-uniform motion, and means for varying the angle between the axis of the work spindle and the plane of cut of the tool mechanism during generation of different teeth of the gear.

18. In a machine for producing irregular gears, a rotatable work spindle, tool mechanism, a cradle upon which one of said parts is mounted and which is oscillatable about an axis inclined to the axis of the work spindle, means for oscillating the cradle, means for rotating the .work spindle comprising a worm and worm wheel, means for moving the worm axially at a varying velocity, means for rotating the worm at a uniform velocity in time with the cradle rotation during cutting of the teeth to generate the tooth profiles, means for producing alternate movements of feed and withdrawal between the work spindle and the tool mechanism, means for rotating the worm independently of the cradle motion during the periods of withdrawal, to index the work spindle, and means for varying the distance between the work spindle and the plane of cut of the tool mechanism for generation of different teeth of the blank.

19. In a machine for producing irregulargears, a rotatable work spindle, tool mechanism, a cradle upon which one of said parts is mounted and which is oscillatable about an axis inclined to the axis of the work spindle, means for oscillating the cradle, means for rotating the work spindle comprising a worm and worm wheel, means for moving the worm axially comprising a rotary cam and a follower engaged therewith and means driven from the worm shaft for rotating said cam, means for rotating the worm at a uniform velocity in time with the cradle motion during cutting, means for producing alternate movements of feed and withdrawal between the tool mechanism and the work spindle, and means for varying the distance between the axis of the work spindle and the plane of cut of the tool mechanism for generation of diflerent teeth of the blank.

20. A method of generating the tooth surfaces of an irregular tapered gear which comprises imparting a cutting motion to the tool while producing a relative rolling movement between the tool and the blank as though the gear being out were rolling without slipping upon a basic gear other than its mate, whose axis is angularly disposed to the axis of the blank and which has identical teeth, uniformly spaced.

21. The method of generating the tooth surfaces of an irregular tapered gear which comprises imparting a cutting motion to the tool while producing a relative rolling movement between the tool and the blank as though the gear being cut were rolling without slipping upon a basic gear, other than its mate, whose axis is angularly disposed to the axis of the blank and which has straight-profiled, identical teeth, uniformly spaced.

22. The method of generating an irregular tapered gear which comprises generating each tooth of the gear by imparting a cutting motion to the tool while producing a relative rolling motion between the tool and the gear blank to generate 10 the tooth profiles of the blank, and. varying the velocity of said relative rolling movement and the angle between the axis of the blank and the cutting plane of the tool for generation of difierent teeth of the blank and periodically indexing the blank, said indexing being of different amounts for successive teeth of the blank.

23. A method of generating an irregular tapered gear which comprises imparting a cutting motion to the tool, alternately moving the tool into and out of engagement with the blank and, while the tool and blank are in cutting engagement, rotating the blank on its axis and producing an additional relative movement between the tool and blank about an axis inclined to the blank axis to generate the tooth profiles, and varying the angle between the axis of the blank and the plane of cut of the tool and the relative ratio of rotation of the blank to said additional relative movement for successive teeth of the blank, and indexing the blank during the periods of withdrawal.

24. The method of generating an irregular tapered gear which comprises imparting a cutting motion to the tool, alternately moving the tool into and out of engagement with the blank, and, while the tool and blank are in cutting engagement, rotating the blank on its axis and producing an additional relative movement between the tool and blank about an axis inclined to thif? blank axis to generate the tooth profiles, and varying the angle between the blank axis and the plane of cut of the tool and the relative ratio of rotation of the blank to said additional relative movement for successive teeth of the blank, and indexing the blank different distances for successive teeth of the blank during the periods of withdrawal.

25. In a machine for generating irregular tapered gears, a work spindle, tool mechanism, means for actuating the tool mechanism, means for rotating the work spindle on its axis and for simultaneously effecting a relative movement of translation between the tool mechanism and the work about an axis inclined to the axis of the 5 work spindle, means for varying the angle between the described axis and the axis of the work spindle for cutting difierent teeth of the blank, means for varying the ratio of said relative rotary and translatory movements for cutting different 50 teeth of the blank, and means for indexing the blank periodically but by different amounts for successive teeth of the blank.

26. In a machine for generating irregular tapered gears, a work spindle, tool mechanism, means for actuating the tool mechanism, means for rotating the work spindle on its axis and for simultaneously effecting a relative movement of translation between the tool mechanism and the work about an axis inclined to the axis of the work spindle, means for varying the angle between the described axis and the axis of the work spindle during generation of the teeth of the blank, means for varying the ratio of said relative rotary and translatorymovements dur- 7 ANU iLAwiwu,

ing generation of the teeth of the blank, and means for indexing the blank periodically but by different amounts for successive teeth of the blank.

27. In a machine for generating irregular tapered gears, a work spindle, a tool having a straight-profiled cutting edge, means for imparting a cutting motion to the tool, means for rotating the work spindle on its axis and for simultaneously effecting a relative movement of translation between the tool mechanism and the work ff y' spindle about an axis inclined to the axis of the work spindle, means for varying the angle between the described axis and the axis of the work spindle during generation of the teeth of the work, means for varying the ratio of said relative rotary and translatory movements during generation of the teeth of the blank, and means for indexing the blank periodically but by different amounts for successive teeth of the blank.

ALLAN H. CANDEE. 

